1. Field of the Invention
The invention relates generally to the field of communications systems that securely provide location information of a tracking unit. More particularly, the present invention relates to an encryption apparatus and methodology for a tracking unit to securely transfer location information over an insecure communication channel. The tracking unit associated with an individual or object uses any of the following: wireless data transfer, wireless location and tracking systems, and wireless communication system (WCS).
2. Description of Related Technology
In conventional communication systems, location information of individuals may be monitored. For instance, location information such as positional coordinates may be tracked or monitored for a variety of individuals, such as children, Alzheimer's syndrome patients, or mentally ill persons. Furthermore, location information for animals, such as cats and dogs, may be tracked using these conventional systems to locate a lost or stolen animal. In other conventional communication systems, scientists, such as zoologists, track, for example, wild animals to study and collect data related to their mating and/or nocturnal behavioral patterns.
In addition, objects are also tracked or located that use these systems. For example, merchants choose to track the location of goods as part of an inventory function and/or an anti-theft mode. In another example, police often use location-tracking systems to facilitate recovery of stolen automobiles, such as the LoJack™ vehicle recovery system offered by the LoJack Corporation of Westwood, Mass., in the United States. Automobile rental agencies often track a location of automobiles that customers rent to ensure their automobile is maintained within a contracted rental use boundary. Other location systems provided in select automobiles assist a driver navigating to a desired destination, such as the OnStar™ system offered by the OnStar Corporation of Detroit, Mich., in the United States.
Global Positioning System (GPS) technology may be incorporated in these conventional communication systems. GPS technology determines positional information of a GPS receiver based on measuring signal transfer times between satellites having known positions and the GPS receiver. The signal transfer time of a signal is proportional to a distance of a respective satellite from the GPS receiver. Consequently, the distance between the satellite and the GPS receiver can be converted, utilizing signal propagation velocity, into a respective signal transfer time. The positional information of the GPS receiver is calculated based on distance calculations from at least four satellites.
As such, GPS technology provides outdoor, line-of-sight communication between a GPS receiver and a centralized station within areas that are unobstructed by fabricated structures and natural features. Fabricated structures may include multi-story buildings, bridges, dams, and the like. Natural features include mountains, hills, valleys, canyons, cliffs, and the like. Exemplary products, such as Wherifone™ and Guardian Lion™, use GPS technology to track individuals and/or objects from a centralized monitoring station.
To protect information associated with tracking individuals and/or objects, the location information needs to be securely transferred to a remote monitoring terminal. Cryptography techniques may be utilized to protect contents of information sent between a tracking device and a monitoring station. A conventional cryptography technique may include Shift Ciphers. Shift Ciphers shift letters using a function, e.g., mod 26, to encrypt and decrypt letters and are limited, in this case, to 26 possible encodings per letter. Another conventional cryptography technique (e.g., Diffie-Hellman) includes generation of a symmetric key. More specifically, a Diffie-Hellman exchange is a cryptographic protocol that allows two parties that have no prior knowledge of each other to jointly establish a shared secret key over an insecure communication channel. The symmetric key generated independently by each is used to encrypt and decrypt subsequent communication. To generate the symmetric key, each party in Diffie-Hellman solves a discrete logarithm problem. However, Diffie-Hellman does not provide authentication of the parties; thus, this approach may be vulnerable to another party establishing the two distinct Diffie-Hellman keys and decrypting the message through performing a multitude a decrypting and/or encrypting steps. Another conventional cryptography technique involves substitution ciphers, e.g., Affine Ciphers. Unfortunately, there are crypto-analysis attack ciphers available to decrypt substitution ciphers.
Another type of security key is a block cipher, such as Advanced Encryption Standard (AES) announced by the National Institute of Standards and Technology (NIST) as U.S. FIPS PUB 197 (FIPS 197) on Nov. 26, 2001. AES became a recognized standard on May 26, 2002. In 2006, AES became one of the most popular algorithms associated with symmetric key cryptography. In many conventional cryptography systems, AES variables include a fixed block size of 128 bits and a key size selected by the parties of 128, 192, or 256 bits. In other conventional AES systems, variables may be specified with key and block sizes in 32 bit multiples having a minimum of 128 bits and a maximum of 256 bits. When utilizing this system, many cryptographers worry security of AES may be inadequate. For instance to achieve a cryptographic break, a 128 bit key AES cryptographic attack requires only 2120 operations as compared to 2128 possible keys. To further increase AES security, larger size keys, e.g., 192 and 256 bits, are utilized at the expense of increased computational burden.
Representative cryptography patents (which are herein incorporated by reference) include U.S. Pat. No. 6,088,453 entitled “Scheme for Computing Montgomery Division and Montgomery Inverse Realizing Fast Implementation” by inventor Atsushi Shimbo that issued Jul. 11, 2000, disclosed an algorithm to perform high speed Montgomery division; U.S. Pat. No. 6,850,252 entitled “Intelligent Electronic Appliance System and Method” by inventor Steven M. Hoffberg, which issued on Feb. 1, 2005, disclosed compressing a video stream compression; and U.S. Pat. No. 6,859,533 entitled “System and Method for Transferring the Right to Encode Messages in a Symmetric Encoding Scheme” by inventor Xin Wang et. al., which issued on Feb. 22, 2005, disclosed methodology to pass encrypted files.
Other conventional cryptographic methodologies (herein incorporated by reference) include those in: U.S. Pat. No. 6,937,726 entitled “System and Method for Protecting Data Files by Periodically Refreshing a Decryption Key” by inventor Xin Wang, which issued on Aug. 30, 2005, disclosed a periodic key refresh procedure; U.S. Pat. No. 7,079,650 entitled “Computing Method Elliptic Curve Cryptography” by inventor Erik Knudsen, which issued on Jul. 18, 2006, disclosed a public/private key encryption scheme; U.S. Pat. No. 7,139,396 entitled “Koblitz Exponentiation with Bucketing” by inventor Peter L. Montgomery, et. al, which issued on Nov. 21, 2006, disclosed a method for modular exponentiation; and US Patent Publication 20070053513 entitled “Intelligent Electronic Appliance System and Method” by inventor Steven M. Hoffberg, which issued on Mar. 8, 2007, disclosed an electronic appliance that interprets motion of a human.
Still other conventional cryptographic methods (that are herein incorporated by reference) include elliptic curve point operations as described in U.S. Patent Application Publication No. US 2004/0114756 published Jun. 17, 2004, entitled “Method for Elliptic Curve Point Multiplication” by inventors Moller et al. and US Patent Application Publication No. US 2004/0010689 by inventors Vanstone, et al., published Jan. 15, 2004, entitled “Method and Apparatus for Performing Elliptic Curve Arithmetic” (which are both herein incorporated by reference).
Still other cryptographic methods include a symmetric encryption/decryption architecture disclosed in Patent Application Publication No. US 2007/0028088, published Feb. 1, 2007, entitled “Polymorphic Encryption Method and System” by inventors Bayrak et al. (which is herein incorporated by reference). In this symmetric decoding/encoding architecture, a 52-letter character set forms a key for encryption/decryption of messages. The key corresponds to all of the uppercase and the lowercase letters in the English alphabet. The encrypted messages may be compressed and an XOR function to thwart a malicious attack. This methodology added to a message length because each letter of a message being randomly assigned a 52 letter designation increases memory storage requirements. In addition, the use of a symmetric encryption/decryption key, once cracked, would allow eavesdroppers to read and transmit messages.
Consequently, what is needed is a cryptographic security scheme to encrypt a message for secure transmission over an insecure communication channel that provides additional advantages over conventional cryptographic security systems. These advantages would include, inter alia, minimal addition of overhead bits to a message, reduced instruction set for encrypting/decrypting messages, a compression algorithm capable of eliminating or reducing a redundancy of message characters, and other features that provide increased security when monitoring data and location information acquired from a tracking device to prevent small byte messages detection by unauthorized individuals.